Within the petroleum industry, crystallization and deposit formations during production, transportation, and storage of crude oils can be detrimental to the operation. These deposits can include organic deposits and inorganic deposits. These deposits and formations can occur on many surfaces within upstream and downstream operations. Further, these deposits can block pores in near-well formations and can form in the production tubing and downstream pipelines. Additionally, these deposits can also reduce pump efficiency.
Paraffinic deposits are comprised of long, straight and branched alkane compounds that are naturally present in crude oils. These alkanes can precipitate out of the crude oil and form paraffinic waxes. These specific deposits can reduce pipe flow, increase fluid viscosity, increase operating cost as efficiency is decreased, and can be challenging to remove.
Asphaltenes are highly prevalent in heavy crude oils and as a result require special attention during extraction and processing of these heavy crude oils. Asphaltene deposits can block reservoir pores in near-well formations, production tubing, and downstream pipelines.
Scale formation can arise in systems that contain ions, including calcium, strontium, and barium cations, and carbonate and sulfate anions. When concentrations and identities of ions provide soluble species then no deposits are formed. However, when concentrations of ions exceed the solubility limit for the particular species, then precipitation can occur and deposits can form. If left untreated, these deposits can have adverse effects on the general system that include fouling, reduction in efficiency, mechanical failures, or shut-down of the system for remediation.
A traditional method used to remove organic deposits from downhole wells is to heat water to a temperature well above the melting point of the organic deposits and then circulate the water down hole through the annular space and returning to the surface through the production tubing. This method can be inadequate in systems where the crude oil has particular components, including paraffin waxes.
Therefore, a need exists for alternative methods and compositions for cleaning and removing deposits on surfaces in an oil or gas well.